garrytheskate Posted October 21, 2020 Share Posted October 21, 2020 HiI may be missing something but I can't see how to turn on loco lights.Thanks Link to comment Share on other sites More sharing options...
ColinB Posted October 21, 2020 Share Posted October 21, 2020 Function F0. Press the function button once, on first function screen press 0, that is F0. Link to comment Share on other sites More sharing options...
Chrissaf Posted October 21, 2020 Share Posted October 21, 2020 Before sending a F0 command to turn on 'Directional Lights' you first have to select the DCC address for the loco that you want to illuminate on your controller. Also, be aware [since your post was non specific in detail] that other lights such as Cab Lights or Carriage Lights will probably be switched on & off using different F numbers. If you are using a R8249, the Hornby data-sheet for this decoder has this function list missing as an over-sight, but most other decoder data-sheets will (should) include a list of the functions and their purpose. However, using F0 to switch on & off 'Directional Lighting' is somewhat a 'de-facto standard' that virtually all decoder manufacturers adopt. Maybe this is the reason that Hornby omitted to document it in their R8249 decoder data-sheet documentation, they just assumed that you would know it. Also, note that these lighting functions operate as a 'toggle'. You send the appropriate function command once to turn the function (lights?) 'on', then you send the same function number again to turn them 'off'. Link to comment Share on other sites More sharing options...
96RAF Posted October 22, 2020 Share Posted October 22, 2020 It is presumed your loco actually has lights installed and is fitted with a decoder. Link to comment Share on other sites More sharing options...
garrytheskate Posted October 22, 2020 Author Share Posted October 22, 2020 Many thanks for your replies. I have installed an R8249 decoder into a hornby class25. I intend to fit LEDs into the head code box controlled as if it was cab lighting. Can I use the green wire from the decoder and if so can I control this with function F0?Regards Link to comment Share on other sites More sharing options...
Chrissaf Posted October 22, 2020 Share Posted October 22, 2020 Can I use the green wire from the decoder and if so can I control this with function F0? No .... see explanation below for the R8249. F0 controls the White and Yellow wires. The voltage on the wires is then manipulated by the direction. Going forward the white wire is switched negative [or more accurately zero volts]. When going in the reverse direction the negative on the white wire is switched off so that the yellow wire is then switched negative instead. In other words, F0 toggles the white and yellow wires to negative [zero volts] subject to the direction of the loco. Forward, white wire 'on' yellow 'off'. Reverse, white wire 'off' yellow wire 'on'. On = negative = zero volts. F1 is used to switch the Green wire negative 'on' and then F1 a second time switches the Green wire 'off'. F2 is use to switch the Purple wire negative 'on' and then F2 a second time switches the Purple wire 'off'. In all cases the 'on' condition is the appropriate wire being switched to 'negative' [zero volts]. The 'off' condition is the wire negative [zero volts] voltage being removed. The 'Blue' wire on the decoder is permanently at a 'Positive' voltage, about 12 to 14 volts. Thus the individual lighting circuits are between the common positive Blue wire and the appropriate white, yellow, green or purple wire dependent upon which F number command is sent, and in the case of F0, also what direction the loco is set to travel in. You MUST include a current limiting resistor for each connected LED, else you will instantly burn out the LED. The value of the resistor can be used to control the LED brightness, but the initial starting point is typically 1,000 Ohms and if dimmer LEDs are required, the value of the resistors could be as high as 5,000 to 7,000 Ohms. This schematic of the R8249 decoder being used with a 'user installed' LED lighting scheme will assist. /media/tinymce_upload/641414b05d692d7bac6a10281a99f540.jpg Link to comment Share on other sites More sharing options...
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